when we can put baby in walker

I am guilty of putting my child in a walker even after reading the KKH article. I guess for just 15mins a day should be quite ok? Anyway I only put my child in after she can comfortably roam around (as my walker is slightly taller and at earlier days she was too short for her feed to touch the ground). She started walking at abt 10mths and running at 12 months. So I didn't use it for too long too.